Custom Config

Precautions

Each account can create up to 50 replica set instances.

Prerequisites

• You have registered a Huawei Cloud account.

You will be additionally charged for using DeC.

Only pay-per-use replica set instances can be purchased through DeC.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select a region and a project.
3. Click in the upper left corner of the page and choose Databases > Document Database Service.
4. On the Instances page, click Buy DB Instance.
5. On the displayed page, click Custom Config.
6. Select a billing mode. Specify instance details and click Next.
   Figure 1 Basic configurations
   

   Table 1 Billing Mode

   Parameter	Description
   Billing Mode	Select a billing mode, Yearly/Monthly or Pay-per-use. For yearly/monthly instances Specify Required Duration, and the system deducts the fees incurred from your account based on the service price. If you do not expect to continue using the instance much after it expires, you can change the billing mode from yearly/monthly to pay-per-use. For details, see Changing the Billing Mode from Yearly/Monthly to Pay-per-Use.. NOTE: Instances billed on a yearly/monthly basis cannot be deleted. They can only be unsubscribed from. For details, see Unsubscribing from a Yearly/Monthly Instance. For pay-per-use instances You are billed for usage based on how much time the service is in use. If you expect to use the service extensively over a long period of time, you can change its billing mode from pay-per-use to yearly/monthly to reduce costs. For details, see Changing the Billing Mode from Pay-per-Use to Yearly/Monthly..
   Region	The region where the resource is located. NOTE: Instances deployed in different regions cannot communicate with each other through a private network, and you cannot change the region of an instance once it is purchased. Exercise caution when selecting a region.
   AZ	An AZ is a part of a region with its own independent power supply and network. AZs are physically isolated but can communicate through internal network connections. Instances can be deployed in a single AZ or three AZs. If your service requires low network latency between instances, you deploy the components of the instance in the same AZ. If you select a single AZ to deploy your instance, anti-affinity deployment is used by default. With an anti-affinity deployment, your primary, secondary, and hidden nodes are deployed on different physical machines for high availability. If you want to deploy an instance across AZs for disaster recovery, select three AZs. In this deployment mode, the primary, secondary, and hidden nodes are evenly distributed across three AZs. NOTE: The 3-AZ deployment is not available in all regions. If the 3-AZ option is not displayed on the page for you to buy an instance, try a different region.
   DB Instance Name	The instance name can be the same as an existing instance name. The instance name that you specify after the purchase. The instance name must contain 4 to 64 characters and must start with a letter. It is case sensitive and can contain letters, digits, hyphens (-), and underscores (_). It cannot contain other special characters. If you purchase multiple DB instances at a time, they will be named with a date, time, and serial number appended in the format "-MMDD-HHmmss-SN". (format: instance_name-MMDD-HHmmss-SN). After the DB instance is created, you can change its name. For details, see Changing an Instance Name.
   Database Type	Community Edition
   DB Instance Type	Select Replica set. A replica set consists of the primary node, secondary node, and hidden node. If a primary node goes down or becomes faulty, a secondary node is automatically assigned to the primary role and continues normal operation. If a secondary node is unavailable, a hidden node will take the role of the secondary to ensure high availability.
   Compatible MongoDB Version	4.2 4.0 3.4 NOTE: DDS 4.2 is restricted for commercial use. For details, see the DDS notices. To use this version, contact customer service to apply for the required permissions.
   Storage Type	If you do not use DeC, the storage type is ultra-high I/O by default. For DeC users, the supported storage types depend on the selected resource type. If you select EVS for Resource Type, Storage Type is set to Ultra-high I/O. If you select DSS for Resource Type, Storage Type can be set to Common I/O, High I/O, or Ultra-high I/O.
   Storage Engine	WiredTiger WiredTiger is the default storage engine of DDS 3.4 and 4.0. WiredTiger provides different granularity concurrency control and compression mechanism for data management. It can provide the best performance and storage efficiency for different kinds of applications. RocksDB RocksDB is the default storage engine of DDS 4.2. RocksDB supports efficient point lookup, range scan, and high-speed write. RocksDB can be used as the underlying data storage engine of MongoDB and is suitable for scenarios with a large number of write operations.
   Specifications	With an x86 architecture, you have the following options: General-purpose (s6): S6 instances are suitable for applications that require moderate performance generally but occasional bursts of high performance, such as light-workload web servers, enterprise R&D and testing environments, and low- and medium-performance databases. Enhanced II (c6): C6 instances have multiple technologies optimized to provide stable powerful compute performance. 25 GE intelligent high-speed NICs are used to provide ultra-high bandwidth and throughput, making it an excellent choice for heavy-load scenarios. It is suitable for websites, web applications, general databases, and cache servers that have higher performance requirements for compute and network resources; and medium- and heavy-load enterprise applications.
   Node Class	For details about the instance specifications, see Instance Specifications. You can change the class of an instance after it is created. For details, see Changing a Replica Set Instance Class.
   Storage Space	If an instance has less than 16 vCPUs, the storage space ranges from 10 GB to 2000 GB. If an instance has more than 16 vCPUs, the storage space ranges from 10 GB to 4000 GB. The value ranges from 10 GB to 2000 GB and must be a multiple of 10. You can scale up an instance after it is created. For details, see Scaling Up a Replica Set Instance. NOTE: If the storage space you purchased exceeds 600 GB and the remaining storage space is 18 GB, the instance becomes Read-only. If the storage space you purchased is less than 600 GB and the storage space usage reaches 97%, the instance becomes Read-only. In these cases, delete unnecessary resources or expand the capacity.
   Disk Encryption	Disabled: Disable encryption. Enabled: Enable encryption. This feature improves data security but slightly affects read/write performance. Key Name: Select or create a private key, which is the tenant key. NOTE: After an instance is created, the disk encryption status and the key cannot be changed. Backup data stored in OBS is not encrypted. The key cannot be disabled, deleted, or frozen when being used. Otherwise, the database becomes unavailable. For details about how to create a key, see "Creating a CMK" in Data Encryption Workshop User Guide.

   Figure 2 Administrator settings
   

   Table 2 Administrator settings

   Parameter	Description
   Password	Configure Enter and confirm the new administrator password. After an instance is created, you can connect to the instance using the password. Skip To log in, you will have to reset the password later on the Basic Information page. If you need to connect to an instance after it is created, locate the instance and choose More > Reset Password in the Operation column to set a password for the instance first.
   Administrator	The default account is rwuser.
   Administrator Password	Set a password for the administrator. The password must be 8 to 32 characters in length and contain uppercase letters, lowercase letters, digits, and at least one of the following special characters: ~!@#%^*-_=+? Keep this password secure. If lost, the system cannot retrieve it for you.
   Confirm Password	Enter the administrator password again.

   Figure 3 Network, Required Duration, and Quantity
   

   Table 3 Network

   Parameter	Description
   VPC	The VPC where your DB instances are located. A VPC isolates networks for different services. It allows you to easily manage and configure private networks and change network configurations. You will need to create or select the required VPC. For details about how to create a VPC, see "Creating a VPC" in Virtual Private Cloud User Guide. For details about the constraints on the use of VPCs, see Connection Methods. If there are no VPCs available, DDS creates one for you by default.
   Subnet	A subnet provides dedicated network resources that are logically isolated from other networks for security reasons. After the instance is created, you can change the private IP address assigned by the subnet. For details, see Changing a Private IP Address. NOTE: IPv6 subnets are not supported. You are advised to create and select IPv4 subnets.
   Security Group	A security group controls access between DDS and other services. If there are no security groups available, DDS creates one for you by default. NOTE: Ensure that there is a security group rule configured that allows clients to access instances. For example, select an inbound TCP rule with the default port 8635, and enter a subnet IP address or select a security group that the instance belongs to.
   SSL	Secure Sockets Layer (SSL) encrypts connections between clients and servers, preventing data from being tampered with or stolen during transmission. You can enable SSL to improve data security. After an instance is created, you can connect to it using SSL.
   Database Port	The default DDS port is 8635, but this port can be modified if necessary. If you change the port, add a corresponding security group rule to allow access to the instance.
   Cross-CIDR Access	Configure If a client and a replica set instance are deployed in different CIDR blocks and the client is not in 192.168.0.0/16, 172.16.0.0/24, or 10.0.0.0/8, configure Cross-CIDR Access for the instance to communicate with the client. NOTE: To ensure the ECS and the DB instance can communicate with each other, configure the connection. Up to 30 CIDR blocks can be configured, and each of them can overlap but they cannot be the same. That is, the source CIDR blocks can overlap but cannot be the same. The CIDR blocks cannot start with 127. The allowed IP mask ranges from 8 to 32. Skip Configure the CIDR block of the client later. After a DB instance is created, you can configure cross-CIDR access by referring to Configuring Cross-CIDR Access.
   Enterprise Project	Only enterprise users can use this function. To use this function, contact customer service. An enterprise project is a cloud resource management mode, in which cloud resources and members are centrally managed by project. Select an enterprise project from the drop-down list. The default project is default.

   Table 4 Required duration and quantity

   Parameter	Description
   Required Duration	The system will automatically calculate the fee based on the validity period you have selected.
   Auto-renew	By default, this option is not selected. If you select this option, the auto-renew cycle is determined by the length of the subscription.
   Quantity	The purchase quantity depends on the replica set instance quota. If your current quota does not allow you to purchase the required number of instances, you can apply for increasing the quota as prompted. Yearly/Monthly instances that were purchased in batches have the same specifications except for the instance name and ID.

   Figure 4 Advanced settings
   

   Table 5 Advanced settings

   Parameter	Description
   Replica Set Parameter Template	The parameters that apply to the replica set instances. After an instance is created, you can change the parameter template you configured for the instance to bring out the best performance. For details, see Editing a Parameter Template.
   Show Original Log	If Show Original Log is enabled, the original slow query logs will be displayed, and the logs will be transferred to an OBS bucket. By default, the system automatically deletes logs from the OBS bucket after 30 days, and the retention period cannot be changed.
   Automated Backup	DDS enables an automated backup policy by default, but you can disable it after an instance is created. An automated full backup is immediately triggered after the creation of an instance. For details, see Configuring an Automated Backup Policy.
   Retention Period (days)	Retention Period refers to the number of days that data is kept. You can increase the retention period to improve data reliability. The backup retention period is from 1 to 732 days.
   Time Window	The backup interval is 1 hour.
   Tags	(Optional) You can add tags to DDS instances so that you can quickly search for and filter specified instances by tag. Each DDS instance can have up to 20 tags. Create a tag. You can create tags on the DDS console and configure the tag key and value. Key: This parameter is mandatory. Each tag key must be unique for each instance. A tag key consists of up to 36 characters. The key must consist of only digits, letters, underscores (_), and hyphens (-). Value: This parameter is optional. The value consists of up to 43 characters. The value must consist of only digits, letters, underscores (_), periods (.), and hyphens (-). Add a predefined tag. Predefined tags can be used to identify multiple cloud resources. To tag a cloud resource, you can select a created predefined tag from the drop-down list, without entering a key and value for the tag. For example, if a predefined tag has been created, its key is Usage and value is Project1. When you configure the key and value for a cloud resource, the created predefined tag will be displayed on the page. After an instance is created, you can click the instance name to view its tags. On the Tags page, you can also modify or delete the tags. In addition, you can quickly search for and filter specified instances by tag. You can add a tag to an instance after the instance is created. For details, see Adding a Tag.

   If you have any question about the price, click Price Details.

   

   Instance performance depends on the specifications you select during creation. The hardware configuration items that can be selected include the instance class and storage space.

7. On the displayed page, confirm the instance details.
   • For yearly/monthly instances
     • If you need to modify the specifications, click Previous to return to the previous page.
     • If you do not need to modify the specifications, read and agree to the service agreement and click Pay Now to go to the payment page and complete payment.
   • For pay-per-use instances
     • If you need to modify the specifications, click Previous to return to the previous page.
     • If you do not need to modify the specifications, read and agree to the service agreement and click Submit to start creating the instance.

8. After a DDS instance is created, you can view and manage it on the Instances page.
   • When an instance is being created, the status displayed in the Status column is Creating. This process takes about 15 minutes. After the creation is complete, the status changes to Available.
   • Yearly/Monthly instances that were purchased in batches have the same specifications except for the instance name and ID.